JPH0589995A - X-ray device - Google Patents

Abstract

PURPOSE:To anticipate the life of an X-ray tube affected by withstand strength failure by adding to an overcurrent detection circuit a circuit for detecting discharge of micro energy. CONSTITUTION:In the case of large discharge in which the pulse width of discharge at an X-ray tube 4 is more than several (ms), the overcurrent detection circuits 14, l4', 15, 15' of overcurrent detection circuits 12, 12' perform detecting action and put an interlocking circuit 10 in action through the action of current relayes 5, 5' and holds a power feed relay l in a cut-off state to cut off power supply. In the case of micro discharge in which the pulse width of discharge is several (mus), only the overcurrent detection circuits 15, 15' perform detecting action and inversion outputs are generated from comparators 7, 7' to indicate generation of the micro discharge that affects the life of a display unit 11. Thereby the frequency of display of micro discharge can be measured and the life of the X-ray tube 4 affected by withstand strength failure can be anticipated and as a result the X-ray tube 4 can be replaced before its life ends.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overcurrent detection circuit for an X-ray tube of an X-ray device.

[0002]

2. Description of the Related Art An example of a conventional overcurrent detecting circuit for an X-ray tube is described in Japanese Patent Publication No. 63-7439. This overcurrent detection circuit consists of a current detection resistor, a noise absorption capacitor, a volume resistor, a reference voltage power supply, a reference voltage setting resistor, and a comparator having a capacitor and a diode. The output is inverted when the input voltage exceeds the reference voltage, that is, when an overcurrent flows. Further, an interlock circuit is provided, and this circuit is operated by the inverted output of the overcurrent detection circuit so that the high voltage current supply relay and the filament heating circuit control relay are turned off.

[0003]

The above-mentioned conventional overcurrent detection circuit detects glow discharge in the X-ray tube, insulation failure of the high-voltage bushing, etc., and operates the interlock circuit to supply a high voltage to the X-ray tube. The main purpose was to shut off the. For this reason, no consideration has been given to the prediction of the life of the X-ray tube. Only when the overcurrent detection circuit operates and the interlock of the device and the discharge display are made, the withstand voltage defect of the X-ray tube is detected, and the X-ray tube is detected. Often it was judged that the life of the. The present invention aims to add the withstand voltage life prediction function of the X-ray tube by having two types of overcurrent detection circuits.

[0004]

In order to achieve the above object, in the present invention, a high voltage obtained from a high voltage generator is applied to X
In an X-ray device that generates X-rays by applying it between the anode and cathode of a X-ray tube, its overcurrent detection circuit has a pulse width of several meters.
An overcurrent detection circuit A for detecting a discharge having a large discharge energy of s or more and an overcurrent detection circuit B for detecting a discharge of a minute energy having a pulse width of about several μs are provided. The overcurrent detection circuit B is used to cut off the high voltage supply to the X-ray tube, and is used to judge the withstand voltage life of the X-ray tube.

[0005]

Of the two types of overcurrent detection circuits according to the present invention, the one that detects a discharge of minute energy having a pulse width of several μs (hereinafter referred to as a slight discharge) has a whisker-like shape with a pulse width of several μs. It is to detect and display the waveform of small discharge and measure the frequency of occurrence during use. Since the discharge energy of this minute discharge is small, the X-ray tube is not damaged immediately, and therefore it is not necessary to interlock the apparatus even if this discharge is detected. However, this minute discharge is related to the life of the X-ray tube, and when the frequency of occurrence is large, a large discharge is generated and the life is reached. In this way, the life of the X-ray tube is correlated with the frequency of occurrence of this minute discharge, so the life of the X-ray tube can be easily predicted from the frequency of occurrence of the minute discharge. Therefore, the limit value as the life for the frequency of occurrence of the slight discharge (it depends on the pipe type, for example, 1/100 to 1
By setting / 1000), the life of the X-ray tube can be judged before the X-ray tube is damaged and becomes unusable.

On the other hand, a large discharge that impairs diagnosis and gives unnecessary X-ray exposure to a patient is a discharge having a pulse width of several ms or more. Since this discharge may damage the X-ray tube or the device, it is necessary to apply an interlock such as a high voltage interruption as in the past.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a circuit diagram showing an embodiment of the X-ray apparatus of the present invention. 1 is a power supply relay, 2 is a high voltage transformer,
Reference numerals 3, 3'represent a rectifying / smoothing circuit, and 4 an X-ray tube. The first overcurrent detection circuit 1 is provided at the neutral point of the rectifying / smoothing circuit 3 on the positive electrode side.
2 is connected, and the second overcurrent detection circuit 12 'is connected to the neutral point of the rectifying / smoothing circuit 3'on the negative electrode side. The first and second overcurrent detection circuits 12 and 12 'have substantially the same configuration. First overcurrent detection circuit 12
Is an overcurrent detection circuit A for detecting a discharge having a large discharge energy with a pulse width of several ms or more (hereinafter referred to as a large discharge).
13 and an overcurrent detection circuit B14 for detecting a slight discharge having a pulse width of several μs. The overcurrent detection circuit A13 includes a current relay 5 that detects a large discharge and a variable resistor 6 that adjusts its operating current. The variable resistor 6 is adjusted to adjust the detection current value for the large discharge of the current relay 5. The current relay 5 has, for example, a current sensitivity of 5 mA and an operating time of 10 ms.
Is used. The overcurrent detection circuit B14 includes a comparator 7, a discharge current detection resistor 8 and a reference voltage generator 9. When a slight discharge occurs, the discharge current is detected by the detection resistor 8 and the output voltage thereof is detected by the comparator 7. Compared with the reference voltage of the reference voltage generator 9, an inverted output is generated when the reference voltage is exceeded, and a minute discharge (or discharge) that affects the life is measured. In this embodiment, the reference voltage is
The voltage is set to 10 to 30 V and the current detection resistor 8 is set to 10 to 20 Ω.

First and second overcurrent detection circuits 12, 12 '
An interlock circuit 10 and a display circuit 11 are connected to. The interlock circuit 10 is an overcurrent detection circuit A1.
It works when the current relay 5 of 3 detects a large discharge and operates, and the power supply is cut off by turning off the power supply relay 1. The display device 11 displays the occurrence of the slight discharge (or discharge) when the overcurrent detection circuit B14 detects the slight discharge (or discharge) and generates an inverted output, and for example, an LED or the like is used.

In the apparatus of the present embodiment, when a discharge is generated in the X-ray tube 4, if the discharge has a large pulse width of several ms or more, the first or second overcurrent detection circuit 12, 12 is generated. ′
Both the overcurrent detection circuit A13 and the overcurrent detection circuit B14 of FIG. At this time, the overcurrent detection circuit A13 activates the interlock circuit 10 by the operation of the current relay 5 to bring the power supply relay 1 into a cutoff state to cut off the power supply (in this case, check the X-ray tube and others for restarting use). is necessary.). An inverted output is generated from the comparator 7 of the overcurrent detection circuit B14, and it is displayed on the display device 11 that discharge that affects the life is generated. In the case of the above-mentioned large discharge, if there is no damage to the X-ray tube or the like as a result of the inspection, use is restarted.

Next, the pulse width of the discharge in the X-ray tube 4 is several μ.
In the case of a slight discharge of s, the overcurrent detection circuit A13 in the first or second overcurrent detection circuit 12 or 12 'does not perform the detection operation, but only the overcurrent detection circuit B14 does the detection operation. As a result, since the interlock circuit 10 does not work, the power supply is not cut off, the comparator 7 of the overcurrent detection circuit B14 produces an inverted output, and it is indicated that the display device 11 is slightly discharged, which affects the life of the display device 11. It is only done.

As described in [Operation], the life of the X-ray tube has a correlation with the frequency of occurrence of the minute discharge. Therefore, by counting the display frequency of the minute discharge by a measuring circuit (not shown). , When the frequency of occurrence of the slight discharge reaches the limit value specified by the tube type, it is judged as the life of the X-ray tube,
Replace the X-ray tube. As a result, since the life of the X-ray tube can be predicted and replaced before the X-ray tube becomes unusable due to a sudden large discharge, the subject is annoying that the diagnosis is interrupted during the X-ray diagnosis. You don't have to pay.

In the present embodiment, the case of using a single-phase power source has been described, but the present invention can be similarly applied to the case of using a three-phase power source.

[0013]

According to the present invention, the life of an X-ray tube due to defective withstand voltage can be predicted in advance, and as a result, it is possible to replace the X-ray tube before its life. Trouble due to defective withstand voltage can be reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of an X-ray device of the present invention.

[Explanation of symbols]

 5 Current relay 5'Current relay 6 Variable resistance 6'Variable resistance 7 Comparator 7'Comparator 8 Current detection resistance 8'Current detection resistance 9 Reference voltage generator 9'Reference voltage generator 10 Interlock circuit 11 Display circuit 12th 1 Overcurrent detection circuit 12 'Second overcurrent detection circuit 13 Overcurrent detection circuit A 14 Overcurrent detection circuit B

Claims (1)

[Claims] 1. An X-ray device for generating an X-ray by applying a high voltage obtained from a high-voltage generator between an anode and a cathode of an X-ray tube, and an overcurrent detecting circuit having a pulse width of several ms.
An overcurrent detection circuit A for detecting a discharge having a large discharge energy and an overcurrent detection circuit B for detecting a discharge of a minute energy having a pulse width of several μs are provided. An X-ray device characterized in that it is used to cut off the high voltage supply to the tube and the overcurrent detection circuit B is used to judge the withstand voltage life of the X-ray tube.